/**
 * 
 */
package com.careye.utils;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.text.DecimalFormat;

/**
 * @author zr
 *
 */
public class FileSizeUtil {
	public static final int SIZETYPE_B = 1;//获取文件大小单位为B的double值
	public static final int SIZETYPE_KB = 2;//获取文件大小单位为KB的double值
	public static final int SIZETYPE_MB = 3;//获取文件大小单位为MB的double值
	public static final int SIZETYPE_GB = 4;//获取文件大小单位为GB的double值
	/**
	 * 获取文件指定文件的指定单位的大小
	 * @param filePath 文件路径
	 * @param sizeType 获取大小的类型1为B、2为KB、3为MB、4为GB
	 * @return double值的大小
	 */
	public static double getFileOrFilesSize(String filePath,int sizeType){
		File file=new File(filePath);
		long blockSize=0;
		try {
			if(file.isDirectory()){
				blockSize = getFileSizes(file);
			}else{
				blockSize = getFileSize(file);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return FormetFileSize(blockSize, sizeType);
	}
	/**
	 * 调用此方法自动计算指定文件或指定文件夹的大小
	 * @param filePath 文件路径
	 * @return 计算好的带B、KB、MB、GB的字符串
	 */
	public static String getAutoFileOrFilesSize(String filePath){
		File file=new File(filePath);
		long blockSize=0;
		try {
			if(file.isDirectory()){
				blockSize = getFileSizes(file);
			}else{
				blockSize = getFileSize(file);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return FormetFileSize(blockSize);
	}
	/**
	 * 获取指定文件大小
	 * @param f
	 * @return
	 * @throws Exception
	 */
	private static long getFileSize(File file) throws Exception
	{
		long size = 0;
		if (file.exists()){
			FileInputStream fis = null;
			fis = new FileInputStream(file);
			size = fis.available();
		}
		else{
			file.createNewFile();
		}
		return size;
	}

	/**
	 * 获取指定文件夹
	 * @param f
	 * @return
	 * @throws Exception
	 */
	private static long getFileSizes(File f) throws Exception
	{
		long size = 0;
		File flist[] = f.listFiles();
		for (int i = 0; i < flist.length; i++){
			if (flist[i].isDirectory()){
				size = size + getFileSizes(flist[i]);
			}
			else{
				size =size + getFileSize(flist[i]);
			}
		}
		return size;
	}
	/**
	 * 转换文件大小
	 * @param fileS
	 * @return
	 */
	private static String FormetFileSize(long fileS)
	{
		DecimalFormat df = new DecimalFormat("#.00");
		String fileSizeString = "";
		String wrongSize="0B";
		if(fileS==0){
			return wrongSize;
		}
		if (fileS < 1024){
			fileSizeString = df.format((double) fileS) + "B";
		}
		else if (fileS < 1048576){
			fileSizeString = df.format((double) fileS / 1024) + "KB";
		}
		else if (fileS < 1073741824){
			fileSizeString = df.format((double) fileS / 1048576) + "MB";
		}
		else{
			fileSizeString = df.format((double) fileS / 1073741824) + "GB";
		}
		return fileSizeString;
	}
	/**
	 * 转换文件大小,指定转换的类型
	 * @param fileS 
	 * @param sizeType 
	 * @return
	 */
	private static double FormetFileSize(long fileS,int sizeType)
	{
		DecimalFormat df = new DecimalFormat("#.00");
		double fileSizeLong = 0;
		switch (sizeType) {
		case SIZETYPE_B:
			fileSizeLong=Double.valueOf(df.format((double) fileS));
			break;
		case SIZETYPE_KB:
			fileSizeLong=Double.valueOf(df.format((double) fileS / 1024));
			break;
		case SIZETYPE_MB:
			fileSizeLong=Double.valueOf(df.format((double) fileS / 1048576));
			break;
		case SIZETYPE_GB:
			fileSizeLong=Double.valueOf(df.format((double) fileS / 1073741824));
			break;
		default:
			break;
		}
		return fileSizeLong;
	}
	
	/** 
     * 获得指定文件的byte数组 
     */  
    public static byte[] getBytes(String filePath,int size){  
        byte[] buffer = null;  
        try {  
            File file = new File(filePath);  
            FileInputStream fis = new FileInputStream(file);  
            ByteArrayOutputStream bos = new ByteArrayOutputStream(size);  
            byte[] b = new byte[size];  
            int n;  
            while ((n = fis.read(b)) != -1) {  
                bos.write(b, 0, n);  
            }  
            fis.close();  
            bos.close();  
            buffer = bos.toByteArray();  
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
        return buffer;  
    } 
}
